Oil burner having air admission and fuel vaporization means



LITTLE OIL BURNER HAVING AIR ADMISSION AND June 23, 1949. H. c.

FUEL vnonzzmxon mmns Filed Nov. 20, 1944 i b c I M ll l u L rllllrlli: HI

2 I L m. C 1

N w H he na June 21; 1949' 2,473,653

2.47am on. BURNER navmo an: ADMISSION AND rum. varonrza'rron mus mm 0. Little, San Rafael, Calif Application November 20, 1944. Serial No. 584,290 Claims. (0!. Isa-91') l The invention relates to a liquid fuel burner andmore particularly to an oil burner such as disclos'ed in my pending application Serial No.

535,321, wherein the burner parts are so arranged that the vaporized fuel mixture leaving or preparing to leave the fuel generating chamber is caused to burn in a zone defined. at least in part, by a heat-radiating element located directly within the chamber and shielding the interior from contact with the flame, the. element serving by reason of the intense heat communi cated to it by the flame, and transmitted by the element to the interior of the chamber, to produce a thorough vaporization of the liquid oil and a thermal cracking oi the vaporized fuel to an extent that more volatile and highly combustible components are produced in the chamber without the attendant production of elemental carbon or soot, and at the same time due to the positioning of the element and the associated parts of the burner, the said components on departing from the chamber and moving through said burning zone, the throat, and the combustion chamber, will be readily consumed to provide a most eiilcient flame.

An object of the invention is to provide a burner of the character described. in which the heatradiating plate is so arranged in the generating chamber that'a maximum quantity of fuel mixture will be most eilfectively subjected to the effect thereof for producing a mixture capable of sustaining a high-temperature, soot-free flame.

, .2 made without departing from the spirit of the present teaching.

In the drawings. Figure 1 is a vertical section through a burner, illustrating one form of the invention. Figure 2 is a plan view of the same burner.

As above explained, the novel means of my invention may be so designed as to adapt it for incorporation in various types of oil burners, particularly in respect to the generating chamber, that is. the chamber or space in which the oil is vaporized and mixed with primary air. In Figures 1 and 2 the said means of my invention is illustrated in connectionwith a burner 5, having a casing t, which defines an elongated generating chamber 1 providing what may be defined as upper and lower zones for receiving respectively vaporized fuel and liquid fuel. At the upper side of one end 8 of the casing 8 there is pro- Another object of the invention is to provide a generator of the character described, in which the heat-radiating element is so arranged in the generating chamber that a thorough admixture of the vaporized oil and air will be permitted in the chamber, and practically all such mixture will be distributed to insure a uniform and eilective action thereon by the element.

a further object oi the invention is to a design and arrange the heat radiation element that it may be effectively incorporated in burners having fuel vaporizing and mixing chambers or either elongated, cylindrical, or other form.

A still further object is to provide an effective arrangement for insuring the heating of the radiation element to a relatively high temperature.

Additional objects will be apparent from the present description considered, together with the accompanying. drawings wherein several preferred'embodiments oi the'invention are set out.

A Itis' to be understood, however, that modifications and variations from these particularly illustrated applications of the inventive concept may be containing portion.

vided the burner throat 8 and, as will be clear from Figure 2, the side walls iii of the casing taper outwardly from the other end I! to the throat- I Oilin liquid form may be supplied to the vaporizing chamber throughan inlet opening it, here shown adjacent the end I2, the oil being admitted so as to provide a pool on the bottom ll. The level of the oil may be con-" trolled by a suitable float valve l3, and ignition for starting may be effected by means of an electrically heated coil l5.

Primary air to the generator is admitted through perforations I! provided in the side wallsof the casing, and the supply of such air may be augmented by admission through valve-controlled openings il, located at the end l2.

"The burner throat 9 is defined in part by an orifice It in the top wall or plate is of a raised portion 20 of the casing, and in part by an orifice 2i registering with the orifice l8 and provided in a ring plate 22 superimposed over top plate is. The plates it and 22 are spaced so as to provide 8' p sage 28 for secondary air to the throat. A combustion chamber 24 is provided over the throat, and the plate 22 conveniently forms the bottom of such chamber.

Supported within the generator chamber by means such as, screws 25 and positioned immediately under the throat orifice I8 is a heat-radiating element 26. The element 26 is spaced from is relatively large as compared to the space" II betweensuch element and the plate It, and pref erabiy the space 3! between the periphery of the element and the sides of the raised portion Zilof the casing corresponds with the space 29. As will be understood, when the burner is in operation, the gas mixture from the generator chamber will be drawn through passages 29 and ill into the burner throat, and in order to provide for a burning zone in space 28 a relatively large concentration of openings 82 are formed in the sides of the raised portion 20 to furnish what at least at low-fire operation serves as secondary air. Likewise a relatively large concentration of openings 83 are formed below the openings 32 so as to provide flame jets designed to impinge directly upon the element during the operation of the burner and thus insure the element being heated to a red hot state. The radiation element or baiiie is fabricated of heat-conducting material, preferably such as iron, stainless steel, etc., or other suitable metal or alloy.

On ignition of the mixture in space 29, the element 28 will become heated over its entire area and thereby cause an intense radiation of heat bustion increases and the radiation element becomes hotter the rate of passage'of air and vaporized fuel through the mixing chamber and adjacent the radiation element will increase correspondingly. element apparently cracks or decomposes (at least part of) the fuel oil vapor into more volatile hydrocarbons, since the flame produced in the combustion zone resembles that of natural gas. When it is stated that the radiant element "actuates the vaporized fuel, this term is intended to include both the action of thermally cracking some of the gaseous hydrocarbons and the action of imparting energy to these and other gaseous hydrocarbons which renders them more susceptible to combustion and/or to subsequent cracking upon entering the burner throat or combustion zone. It will be evident that, owing to the relatively great expanse of the radiating element, 0. large spread of the fuel mixture will be provided before the mixture can pass into the burning zone in the space 29, so that not only will a thorough mixing of the vapor and air be produced, but an intimate contact of all the mixture with the radiating plate will be assured, and preferably a downwardly extending peripheral flange 34 is provided around the radiating plate in order to increase said action.

Itv is important to note that, by reason of the relatively restricted cross-sectional area of the spaces or passages 29 and 3 l, the flow of the mixturewill be appreciably reduced in volume, and since the supply of air from the openings 32 will continue uninterrupted, the ratio of the air to the fuel will be increased, thereby insuring the most effective burning of the partially cracked oil vapor. Furthermore the streams of air from openings 32 directed completely around and straight into passage 29 provides for a thorough injection and penetration of the air in the mixture admitted tothe passage and in this way the effective burning is additionally assured.

The effective low-flre burning, as above described, is extremely important for the economical operation of the burner, and at the same time the arrangement is such that the burner is very efliclent for high-fire operation, for while the burning zone on high-fire operation moves high 0n the other hand, the radiationup into throat and combustion chamber, the

eflicient vaporization of the fuel and the conditioning of the mixture is maintained. As will be apparent to those skilled in the art, the relationships and sizes of the various parts, chambers .and passages are of utmost importance in providing a burner which will operate in the effective manner hereinabove set forth, and while I have not given any dimensions for the parts, passages. etc., in the drawings, I have found that the burner when constructed with such parts, etc., in the proportions shown in the drawings will provide for efficient operation with most liquid fuels.

In actual practice, the burner when provided with the radiating plate and arrangement of my invention, as compared to a corresponding burner without the element. will operate with equal effectiveness with one-third the draft, and will have an oil-burning capacity far greater. Furthermore, the burner with my element will have a C0: percentage far greater than a corresponding burner without the element. In addition, the present burner will burn with a transparent, blue-white flame and without free carbon, while the burner without the element under the same conditions will burn with a yellow flame and produce free carbon. Moreover, in my burner there is no burning below the radiating plate, and no products of combustion are present in the primary mixture, as the activation produced by the radiation plate converts the vapor and the mixture in the more volatile gases, from which practically all free carbon is absent. On the other hand, without the radiating plate, partial combustion will take place in the generating chamber and products of combustion will mix with the primary mixture of the vapor and air, a condition which is most undesirable.

I claim:

1. In a liquid fuel burner, means forming a horizontally-elongated fuel vaporizing and air admixing chamber provided with a plurality of air inlets in its side walls, means for delivering a regulated amount of liquid fuel to the lower part of said chamber, a heat conducting plate mounted adjacent the top of said chamber and provided with a downwardly directed flange around its periphery, means adjacent the top of said chamber providing a burner throat of smaller circumference than and located proximately above said plate, the flange of said plate being spaced from said chamber side walls so as to allow passage of fuel vapor from said chamber into said burner throat, a combustion chamber above said burner throat, means to supply air to the space between the throat and the plate, means for supplying air to the vaporizing chamber directly from the exterior thereof and toward said flange, and means for supplying secondary air to the throat above said space.

2. A liquid fuel burner comprising a chamber having a lower liquid fuel receiving zone and an upper vaporized fuel receiving zone, air inlet means associated with the upper zone of said chamber, means for delivering a regulated amount of liquid fuel to the lower zone of said chamber to maintain a pool of fuel therein, means communicating with said upper zone defining a burner throat, a heat radiating plate positioned in the upper of said zones and arranged in a position relative to said throat so as to define with sides and top of the chamber a relatively restricted passage for vaporized fuel and air flowing from the lower zone of the chamber to the throat, means inducing air into said restricted passage adjacent said throat directly from the exterior of said chamber, and means for directing air directly from the exterior of the chamber into said restricted passage between said last means and the lower zone of said chamber to combine with vaporized fuel in the chamber to form a fuel mixture providing when ignited a jet of flame against said plate.

3. A liquid fuel burner comprising a chamber having a lower liqued fuel receiving zone and an upper vaporized fuel receiving zone, air inlet means associated with the upper zone 'of said chamber, means for delivering a regulated amount of liquid fuel to the lower zone of said chamber, means communicating with said chamber defining a burner throat, a heat radiating plate positioned within said upper zone and arranged relative to said throat so as to define with sides of the chamber a relatively restricted passage for vaporized fuel and air flowing from the chamber to the throat, means inducing air into said restricted passage between said chamber and said throat directly from the exterior of said chamber, means for directing air directly from the exterior of the chamber into said restricted passage between said last means and said chamber to combine with vaporized fuel therein to form a fuel mixture providing when ignited a jet of flame against said plate, said plate being substantially imperforate and of larger cross-sectional area than said throat to prevent intercommunication between the throat and chamber except by way of said passage, and a downwardly extending, peripheral extension on said plate substantially oppo-' site said first air inducing means. 4. A liquid fuel burner comprising a horizontally elongated casing defining a correspondingly shaped liquid fuel-vaporizing and air-mixing chamber and formed with a vertical partially and extension and being of greater area than said-throat and of lesser area than the extension, said plate defining with the top and sides of the extension a relatively restricted passage extending around and over said plate and communicating with said throat and the pool on the bottom of the chamber, and air inlet means to said passage in the sides of said extension.

5. A liquid fuel burner comprising a casing having side walls and providing a fuel-vaporizing and'air-mixing chamber having a top wall with a burner throat therein, said chamber formed for containing a pool of fuel for exposure therein, means for delivering a regulatable amount of fuel to said chamber, a heat radiating plate in said chamber opposite said throat and spaced from said side walls andtop wall to form a.

munication with the liquid fuel pool in the.

chamber.

HARRY C. LITTLE.

REFERENCES CITED The following referenlces are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 704,669 Tucker July 15, 1002 1,031,473 Sexton et a1 July 2, 1912 1,512,869 Valjean Oct. 21, 1924 1,553,661 Becker Sept. 15, 1925 1,639,202 Valjean Aug. 16, 1927 2,109,946 Little Mar. 1,1938 2,219,349 Turner Oct. 29, 1940 2,259,743 Fletcher Oct. 21, 1941 2,261,814 Suchland Nov. 4, 1941 2,272,423 Moore Feb. 10. 1942 FOREIGN PATENTS Number Country Date,

392,371 France Sept. 2-3, 1908 818,088 France June 7, 1937 274,234 Italy May 15, 1930 

